Use of the lymphocyte transformation test in the diagnosis of DRESS syndrome induced by ceftriaxone and piperacillin-tazobactam: two case reports.

Drug-related rash with eosinophilia and systemic symptoms (DRESS) syndrome, or drug-induced hypersensitivity syndrome (DIHS), is a life-threatening multiorgan systemic reaction characterized by rash, fever, lymphadenopathy, hepatitis, and leukocytosis with eosinophilia. Aromatic anticonvulsant drugs and allopurinol have been reported to be the most frequent eliciting agents. Our search of the literature revealed only 2 cases induced by piperacillin and 1 case by ceftriaxone.We present 2 cases of DRESS syndrome induced by the beta-lactam drugs ceftriaxone and piperacillin-tazobactam. An allergological workup including skin prick test, intradermal tests, patch tests, and lymphocyte transformation test (LTT) was performed. LTT was shown to be a useful technique in both cases to help to identify the drugs involved.